*{margin:0;padding:0}

/*工具*/
.full{width:100%;height:100%;}
.absolute{position:absolute;}
.relative{position:relative;}

/*动画*/
@keyframes arrowing{0%{transform:translateY(-5px);opacity:.8}50%{transform:translateY(10px);opacity:1}to{transform:translateY(-5px)}}
@-webkit-keyframes arrowing{0%,to{opacity:.8}0%{-webkit-transform:translateY(-5px)}50%{-webkit-transform:translateY(10px);opacity:1}to{-webkit-transform:translateY(-5px);opacity:.8}}